const { Readable } = require("stream");

let reader = new Readable();

for(let c = 'a'.charCodeAt(0); c <= 'z'.charCodeAt(0);  c++ ) {
    reader.push(String.fromCharCode(c));
}

reader.push("tsh");

reader.push(null);

console.log(reader.read().toString());



// reader.pipe(process.stdout)